Space-X wants to be regulated under the Railway Labor Act? [1] They should be careful of what they ask for. Some anti-union activities such as fussing with the bargaining unit definition don't apply under the RLA. Space-X is going to end up as a union shop.

Airlines are under the Railway Labor Act because Congress put them there in 1932, and they are almost totally unionized.

[1] https://nmb.gov/NMB_Application/wp-content/uploads/2020/04/R...